The whole existence and their space-time acts like a infinite blockchain.
When something starts, is because something had ended before. Nothing can start from nothing.
When you see the genesis block, before it there are other infinite blocks.
And the latest block is connected with other newer blocks you cannot see, but they depends upon it.
As for every begin there is a end, for every end there is a new begin.
If some things exists, its because other things exists.
If every thing has been generated, its because nothing existing had declared it.
Even the not existing needed to exist to be declared as non existing; that generates everything.
If every thing exists to form the space, every thing forming the times are already existing.
More than one of same thing can't exist, but when it isn't existing it needs to exist.
So, in a timing that can't be metered, when there is a certain time on this universe, there is a previous trace of it on another universe, and this time of this universe is a trace of a future time already existing on another universe.
All timelines and spaces are already generated (because they can't be inexistent, everything needs to exist) and are immutably running now. There is not a end or a begin, but everything exists and are working in parallel and connected. But one space-time can't be equal other, and equal things or events can't occur.
Every time (that can't be metered) that passes, you're a different version from yourself. There are different synapsis on your brain and, more widely referring, there are different formations of your atoms. Those things are linked with the time. Using as example, when you paint your hair according to some achievement. Now you're with blue hair, but on other timeline there is the previous version of you with black hair. But that is even quicker: when you're reciting the alphabet, when you're saying "B", there is a previous timeline of you saying "A" (because it can't be inexistent, as everything can't be inexistent and are instantly spawn to existence) and a future timeline of you saying "C" (because to exist a timeline, even you seeing it as current, there were a previous, and your own timeline is also a previous of a future one).
Everything exists at same time in parallel - and connected - but not equal.
All space-time and its variations are already generated, connected to each other in a infinite flow.
A possibility that a person can't be generated again: is infinite the amount of combination of characteristics to create a unique person?
But even being greater and infinite to our vision, those number of variations can be huge, but aren't infinite.
When all example 100,000,000,000,000,000,000,000,000,000 are generated, the demand has been supplied. When there is just a number greater than this, it acts like a reset, and the next numbers are exact as the previous (as the demand needs to be infinitely supplied). There can't be equal things at same space/time.
Like as some stars are dead but new ones are generated, the generation of loads of persons and things is unlimited.
If you can't born again, then you could not born once.